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Turbulent convection in a Rayleigh-Bénard cell with solid horizontal plates of finite conductivity

Czarnota, Tomasz and Wagner, Claus (2011) Turbulent convection in a Rayleigh-Bénard cell with solid horizontal plates of finite conductivity. STAB DGLR-Fach-Symposium 2010, AG STAB, Berlin, Deutschland.

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Abstract

For the present study turbulent thermal convection in a rectangular Rayleigh-Bénard cell filled with air (Prandtl number Pr=0.7) is equipped with heating and cooling plates with finite thickness, and hence finite conductivity. To obtain reliable results for Rayleigh numbers Ra≈10^7, Direct Numerical Simulations (DNS) of turbulent Rayleigh-Bénard convection as well as of the heat transport between the plates are performed with a high-order finite volume method. Our results are compared with those obtained by Kaczorowski and Wagner (2007, 2009) who studied Rayleigh-Bénard convection in the same cell and for the same Pr and Ra. It is found, that the material properties of the horizontal solid plates affect the boundary conditions at the solid-fluid interfaces. In particular, thermal plumes interacting with poorly conducting plates modify the plate temperature such that the local temperature at the solid-fluid interfaces differs up to 10% to the plate temperature of infinite conductivity plates. Further, the lower temperature difference between top and bottom interfaces leads to lower effective Rayleigh numbers for the poorly conducting plates. The present analysis shows that the temperature fluctuations in the boundary layer and at the interfaces are similar for highly conducting and infinitely thin plates. Further, we conclude that the solid plates have a damping effect on the temperature fluctuations in the boundary layer and the interaction of the large scale flow structures with the fluid boundaries causes temperature fluctuations at the interfaces.

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Turbulent convection in a Rayleigh-Bénard cell with solid horizontal plates of finite conductivity
Authors:
AuthorsInstitution or Email of Authors
Czarnota, TomaszTomasz.Czarnota@dlr.de
Wagner, ClausClaus.Wagner@dlr.de
Date:2011
Refereed publication:No
In ISI Web of Science:No
Page Range:pp. 186-187
Series Name:STAB Mitteilung 2011
Status:Published
Keywords:DNS, Rayleigh-Bénard, convection
Event Title:STAB DGLR-Fach-Symposium 2010
Event Location:Berlin, Deutschland
Event Type:national Conference
Event Dates:AG STAB
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Fluid Systems
Deposited By: Tomasz Czarnota
Deposited On:21 Nov 2011 13:48
Last Modified:12 Dec 2013 21:23

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